#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <wchar.h>
#include <wctype.h>
#include <limits.h>
#include <string.h>
#include <stdint.h>

#include "stdio_impl.h"
#include "shgetc.h"
#include "intscan.h"
#include "floatscan.h"

#define SIZE_hh -2
#define SIZE_h  -1
#define SIZE_def 0
#define SIZE_l   1
#define SIZE_L   2
#define SIZE_ll  3

static void store_int(void *dest, int size, unsigned long long i)
{
    if (!dest) return;
    switch (size) {
    case SIZE_hh:
        *(char *)dest = i;
        break;
    case SIZE_h:
        *(short *)dest = i;
        break;
    case SIZE_def:
        *(int *)dest = i;
        break;
    case SIZE_l:
        *(long *)dest = i;
        break;
    case SIZE_ll:
        *(long long *)dest = i;
        break;
    }
}

static void *arg_n(va_list ap, unsigned int n)
{
    void *p;
    unsigned int i;
    va_list ap2;
    va_copy(ap2, ap);
    for (i=n; i>1; i--) va_arg(ap2, void *);
    p = va_arg(ap2, void *);
    va_end(ap2);
    return p;
}

int vfscanf(FILE *restrict f, const char *restrict fmt, va_list ap)
{
    int width;
    int size;
    int alloc = 0;
    int base;
    const unsigned char *p;
    int c, t;
    char *s;
    wchar_t *wcs;
    mbstate_t st;
    void *dest=NULL;
    int invert;
    int matches=0;
    unsigned long long x;
    long double y;
    off_t pos = 0;
    unsigned char scanset[257];
    size_t i, k;
    wchar_t wc;

    FLOCK(f);

    if (!f->rpos) __toread(f);
    if (!f->rpos) goto input_fail;

    for (p=(const unsigned char *)fmt; *p; p++) {

        alloc = 0;

        if (isspace(*p)) {
            while (isspace(p[1])) p++;
            shlim(f, 0);
            while (isspace(shgetc(f)));
            shunget(f);
            pos += shcnt(f);
            continue;
        }
        if (*p != '%' || p[1] == '%') {
            shlim(f, 0);
            if (*p == '%') {
                p++;
                while (isspace((c=shgetc(f))));
            } else {
                c = shgetc(f);
            }
            if (c!=*p) {
                shunget(f);
                if (c<0) goto input_fail;
                goto match_fail;
            }
            pos += shcnt(f);
            continue;
        }

        p++;
        if (*p=='*') {
            dest = 0; p++;
        } else if (isdigit(*p) && p[1]=='$') {
            dest = arg_n(ap, *p-'0'); p+=2;
        } else {
            dest = va_arg(ap, void *);
        }

        for (width=0; isdigit(*p); p++) {
            width = 10*width + *p - '0';
        }

        if (*p=='m') {
            wcs = 0;
            s = 0;
            alloc = !!dest;
            p++;
        } else {
            alloc = 0;
        }

        size = SIZE_def;
        switch (*p++) {
        case 'h':
            if (*p == 'h') p++, size = SIZE_hh;
            else size = SIZE_h;
            break;
        case 'l':
            if (*p == 'l') p++, size = SIZE_ll;
            else size = SIZE_l;
            break;
        case 'j':
            size = SIZE_ll;
            break;
        case 'z':
        case 't':
            size = SIZE_l;
            break;
        case 'L':
            size = SIZE_L;
            break;
        case 'd': case 'i': case 'o': case 'u': case 'x':
        case 'a': case 'e': case 'f': case 'g':
        case 'A': case 'E': case 'F': case 'G': case 'X':
        case 's': case 'c': case '[':
        case 'S': case 'C':
        case 'p': case 'n':
            p--;
            break;
        default:
            goto fmt_fail;
        }

        t = *p;

        /* C or S */
        if ((t&0x2f) == 3) {
            t |= 32;
            size = SIZE_l;
        }

        switch (t) {
        case 'c':
            if (width < 1) width = 1;
        case '[':
            break;
        case 'n':
            store_int(dest, size, pos);
            /* do not increment match count, etc! */
            continue;
        default:
            shlim(f, 0);
            while (isspace(shgetc(f)));
            shunget(f);
            pos += shcnt(f);
        }

        shlim(f, width);
        if (shgetc(f) < 0) goto input_fail;
        shunget(f);

        switch (t) {
        case 's':
        case 'c':
        case '[':
            if (t == 'c' || t == 's') {
                memset(scanset, -1, sizeof scanset);
                scanset[0] = 0;
                if (t == 's') {
                    scanset[1+'\t'] = 0;
                    scanset[1+'\n'] = 0;
                    scanset[1+'\v'] = 0;
                    scanset[1+'\f'] = 0;
                    scanset[1+'\r'] = 0;
                    scanset[1+' '] = 0;
                }
            } else {
                if (*++p == '^') p++, invert = 1;
                else invert = 0;
                memset(scanset, invert, sizeof scanset);
                scanset[0] = 0;
                if (*p == '-') p++, scanset[1+'-'] = 1-invert;
                else if (*p == ']') p++, scanset[1+']'] = 1-invert;
                for (; *p != ']'; p++) {
                    if (!*p) goto fmt_fail;
                    if (*p=='-' && p[1] && p[1] != ']')
                        for (c=p++[-1]; c<*p; c++)
                            scanset[1+c] = 1-invert;
                    scanset[1+*p] = 1-invert;
                }
            }
            wcs = 0;
            s = 0;
            i = 0;
            k = t=='c' ? width+1U : 31;
            if (size == SIZE_l) {
                if (alloc) {
                    wcs = malloc(k*sizeof(wchar_t));
                    if (!wcs) goto alloc_fail;
                } else {
                    wcs = dest;
                }
                st = (mbstate_t){0};
                while (scanset[(c=shgetc(f))+1]) {
                    switch (mbrtowc(&wc, &(char){c}, 1, &st)) {
                    case -1:
                        goto input_fail;
                    case -2:
                        continue;
                    }
                    if (wcs) wcs[i++] = wc;
                    if (alloc && i==k) {
                        k+=k+1;
                        wchar_t *tmp = realloc(wcs, k*sizeof(wchar_t));
                        if (!tmp) goto alloc_fail;
                        wcs = tmp;
                    }
                }
                if (!mbsinit(&st)) goto input_fail;
            } else if (alloc) {
                s = malloc(k);
                if (!s) goto alloc_fail;
                while (scanset[(c=shgetc(f))+1]) {
                    s[i++] = c;
                    if (i==k) {
                        k+=k+1;
                        char *tmp = realloc(s, k);
                        if (!tmp) goto alloc_fail;
                        s = tmp;
                    }
                }
            } else if ((s = dest)) {
                while (scanset[(c=shgetc(f))+1])
                    s[i++] = c;
            } else {
                while (scanset[(c=shgetc(f))+1]);
            }
            shunget(f);
            if (!shcnt(f)) goto match_fail;
            if (t == 'c' && shcnt(f) != width) goto match_fail;
            if (alloc) {
                if (size == SIZE_l) *(wchar_t **)dest = wcs;
                else *(char **)dest = s;
            }
            if (t != 'c') {
                if (wcs) wcs[i] = 0;
                if (s) s[i] = 0;
            }
            break;
        case 'p':
        case 'X':
        case 'x':
            base = 16;
            goto int_common;
        case 'o':
            base = 8;
            goto int_common;
        case 'd':
        case 'u':
            base = 10;
            goto int_common;
        case 'i':
            base = 0;
        int_common:
            x = __intscan(f, base, 0, ULLONG_MAX);
            if (!shcnt(f)) goto match_fail;
            if (t=='p' && dest) *(void **)dest = (void *)(uintptr_t)x;
            else store_int(dest, size, x);
            break;
        case 'a': case 'A':
        case 'e': case 'E':
        case 'f': case 'F':
        case 'g': case 'G':
            y = __floatscan(f, size, 0);
            if (!shcnt(f)) goto match_fail;
            if (dest) switch (size) {
            case SIZE_def:
                *(float *)dest = y;
                break;
            case SIZE_l:
                *(double *)dest = y;
                break;
            case SIZE_L:
                *(long double *)dest = y;
                break;
            }
            break;
        }

        pos += shcnt(f);
        if (dest) matches++;
    }
    if (0) {
fmt_fail:
alloc_fail:
input_fail:
        if (!matches) matches--;
match_fail:
        if (alloc) {
            free(s);
            free(wcs);
        }
    }
    FUNLOCK(f);
    return matches;
}

weak_alias(vfscanf,__isoc99_vfscanf);
